Optical disc, optical disc recording apparatus, and optical disc recording method

ABSTRACT

Drive information is updated to always include the recording/playback conditions determined from the most recent learning process on a data recording medium. The data recording medium has a data recording area for recording data, and a drive information area for recording drive information. The drive information includes a plurality of drive-specific information records. Each of the plural drive-specific information records defines the operating conditions of the data recording and playback apparatus when a data recording and playback apparatus that can load and access the data recording medium reads or writes data. The plural drive-specific information records are arranged chronologically according to when the information was recorded to the data recording medium.

This application is a divisional application of Ser. No. 10/519,535,filed Aug. 4, 2005 now U.S. Pat. No. 7,539,111 which is a National Stageof International Application No. PCT/JP2003/008262, filed Jun. 30, 2003.

TECHNICAL FIELD

The present invention relates to an optical disc having a driveinformation area for recording a plurality of recording/playbackconditions and other drive information, and to a recording apparatus anda recording method for recording to this optical disc.

BACKGROUND TECHNOLOGY

As optical discs have increased in recording density and capacity,assuring optical disc reliability has become increasingly important. Toassure this reliability, optical disc drives use a learning process todetermine the recording and playback conditions of the disc. Thislearning process is taught, for example, in Japanese Unexamined PatentAppl. Pub. 2001-338422.

These recording and playback conditions depend greatly upon thecharacteristics of the optical disc and the characteristics of theoptical disc drive. As a result, the learning process used to determinethe recording/playback conditions must be executed every time theoptical disc drive is started after an optical disc is loaded, andwhenever there is a change in either optical disc or optical disc drivecharacteristics due to such factors as a change in temperature.

Even more recently, further advances in optical disc recording densityand storage capacity have made it necessary to determine therecording/playback conditions even more precisely. However, determiningthe recording/playback conditions more precisely by means of thislearning process means that the learning process takes more time. As aresult, the optical disc drive spends more time waiting for recording orplayback to start.

SUMMARY OF THE INVENTION

The present invention is directed to resolving the foregoing problems,and an object of this invention is to provide an optical disc wherebythe time required for the learning process to determine therecording/playback conditions can be shortened.

To achieve this object, an optical disc according to the presentinvention has a data recording area for recording data and a driveinformation area for recording drive information. The drive informationarea stores a plurality of recording/playback conditions, and theplurality of recording/playback conditions are arranged chronologicallyaccording to when the conditions are recorded to the disc.

A further optical disc according to the present invention has aplurality of recording layers with each recording layer read by a readbeam incident thereto from the same side of the disc. A driveinformation area for recording drive information is provided on at leastone of the plurality of layers, and an unrecorded blank area is providedin the other recording layers at the same radial position as the driveinformation area.

A plurality of recording/playback conditions are thus recordedchronologically in the order in which the recording/playback conditionsare recorded to an optical disc according to the present invention. Thedrive information is therefore assured of always containing the mostrecent recording/playback conditions.

Furthermore, the radial position where the drive information area isrendered in one recording layer is left unrecorded and blank in theother recording layers of a multilayer optical disc according to thepresent invention, thereby assuring that the drive information can beread stably.

Other objects and attainments together with a fuller understanding ofthe invention will become apparent and appreciated by referring to thefollowing description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the layout of an optical disc 101 according to a firstembodiment of the present invention;

FIG. 2 shows the logic structure of areas in the optical disc shown inFIG. 1;

FIG. 3 shows an example of an ECC block;

FIG. 4 shows the structure of the drive information area;

FIG. 5 shows the data layout in the drive information area;

FIG. 6 shows the data layout in the drive information area;

FIG. 7 shows the data layout in the drive information area;

FIG. 8 shows the data layout in the drive information area;

FIG. 9 shows the data layout in the drive information area;

FIG. 10 shows the data layout in the drive information area;

FIG. 11 is a block diagram of an optical disc drive;

FIG. 12 is a flow chart of the optical disc drive operation;

FIG. 13 shows the structure of an optical disc with two recordinglayers;

FIG. 14 shows the logic structure of areas in an optical disc accordingto a second embodiment of the present invention;

FIG. 15 shows the logic structure of areas in an optical disc accordingto a third embodiment of the present invention;

FIG. 16 shows the data layout in the drive information area;

FIG. 17 shows the data layout in the drive information area; and

FIG. 18 shows the data layout in the drive information area.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A data recording medium according to the present invention has a driveinformation area for recording drive-specific information such asrecording and playback conditions. A data recording and playbackapparatus acquires the recording/playback conditions through a learningprocess, and records the recording/playback conditions to the driveinformation area of the data recording medium. The recording/playbackconditions recorded to the drive information area of the data recordingmedium are read and used to acquire new recording/playback conditionsthe next time the learning process is executed.

These recording/playback conditions are the operating conditions used bythe optical disc drive when the optical disc drive records informationto an optical disc or reproduces recorded information from the opticaldisc.

The recording/playback conditions also include at least one of thefollowing: pulse conditions relating to the laser pulse emitted to theoptical disc, servo conditions controlling servo operation duringrecording and playback, and playback signal processing conditions forprocessing the playback signal.

The pulse conditions include, for example, the power of the laser pulseemitted to the optical disc during recording, or the laser pulseconditions for forming marks (the smallest unit of information) on theoptical disc. When marks are formed on the optical disc by emitting aplurality of pulses to the optical disc from the leading edge to thetrailing edge of the mark, the pulse conditions include at least theoutput timing and length of the first pulse, and the pulse power of thelaser beam in this first pulse, which corresponds to the leading end ofthe mark, or the output timing and length of the last pulse, and thepower of the laser beam in the last pulse, which corresponds to thetrailing end of the mark.

The recording/playback conditions could alternatively be the settings ofvarious circuits contained in the data recording and playback apparatus,or codes denoting those settings.

Thus, reusing the recording/playback conditions recorded in the driveinformation area of the data recording medium simplifies the learningprocess. As a result, less time is needed to complete the learningprocess, and the data recording and playback apparatus thus spends lesstime waiting before recording or playback can begin.

Preferred embodiments of the present invention are described in detailnext below with reference to the accompanying figures.

Embodiment 1

FIG. 1 shows the arrangement of a data recording medium 101 according toa first embodiment of the present invention.

This data recording medium 101 is an optical disc having a plurality ofconcentric tracks 102. Alternatively, a single spiral track 102 or aplurality of spiral tracks 102 could be formed to the optical disc 101.

The track area of the optical disc 101 includes a lead-in area 103, datarecording area 104, and lead-out area 105.

Parameters required to access the optical disc 101 are recorded in thelead-in area 103. The lead-in area 103 is formed at the insidecircumference portion of the optical disc 101.

The lead-out area 105 could also be used to record parameters requiredto access the optical disc 101. The lead-out area 105 is located at theoutside circumference portion of the optical disc 101.

Data is recorded and reproduced in the data recording area 104.

FIG. 2 shows the logic structure of the lead-in area 103, data recordingarea 104, and lead-out area 105 on the optical disc 101 shown in FIG. 1.

The lead-in area 201 includes a prerecorded area 204 and a recordabledata recording area 205 for recording data. The prerecorded area 204stores optical disc 101 identification data, for example, recorded in awobble track, embossed pits, or wobbled embossed pits.

The prerecorded area 204 includes a protected zone 208 as a buffer, anda control data zone 209. The control data zone 209 stores at least oneof the following as optical disc 101 identification information: disctype, disc capacity, disc structure, channel bit, data zone addressinformation, data rate, maximum playback power, recording powerinformation, recording pulse position information, and disc-specificinformation.

The data recording area 205 includes a protected zone 210, a reservedzone 211 enabling future development, a test zone 212 used for testingthe optical disc 101, a buffer zone 213, a drive information zone 214used for storing information such as the optical disc 101characteristics, and a buffer zone 215. If the track pitch differs inthe prerecorded area 204 and data recording area 205, the protected zone210 can be used as a track pitch transition area.

The data recording area 202 includes a data recording area 206 forrecording user data, for example. The data recording area 206 includes auser data recording zone 216.

The lead-out area 203 includes a recordable data recording area 207 forrecording data. The data recording area 207 includes a buffer zone 217,a reserved zone 218 enabling future development, a buffer zone 219, anda protected zone 220 where data is not recorded.

The drive information zone 214 is segmented into 2048 ECC blocks(clusters), for example. The ECC blocks are used for calculating anerror correction code. The error correction code is calculated for eachECC block. Each ECC block is segmented into 32 sectors, for example.

FIG. 3 shows an example of the ECC block structure. To achieve a higherror correction capability and low redundancy in a high capacityoptical disc, each ECC block is divided into 32 sectors. For simplicity,however, one ECC block is divided into only 4 sectors in the exampleshown in FIG. 3.

As shown in FIG. 3, each ECC block includes 172 bytes×48 rows of MainData, Parity of Inner Code PI acquired by calculating the errorcorrection code for each row of Main Data, and Parity of Outer Code POacquired by calculating the error correction code for each verticalcolumn of Main Data.

Error correction codes including inner code parity and outer code parityare generally called product codes. A product code affords strong errorcorrection of both random errors and burst errors (errors that areconcentrated locally), such as where there is both random error and aburst error across two rows due to a scratch. Most such burst errors are2-byte outer code errors and can be corrected. In a column where thereare many random errors, however, correction using the outer code is notpossible and errors remain, but these remaining errors can usually becorrected using the inner code. Even if inner code correction leavessome errors, these errors can be further reduced by applying outer codecorrection again. Redundant parity is suppressed and good errorcorrection is assured by using this type of product code in DVD media.More specifically, user data capacity can be increased according to thedecrease in redundant parity data.

As shown in FIG. 3, the Parity of Outer Code PO for the ECC block isevenly distributed one row per sector. As a result, one sector thuscomprises 182 bytes×13 rows of data.

When the optical disc drive is instructed to record or play an opticaldisc 101 loaded in the optical disc drive by sector unit, the opticaldisc drive reads the ECC block containing the specified sector from theoptical disc 101, applies error correction, and records only the datacorresponding to the specified sector to the optical disc 101.

When the optical disc drive is instructed to record an optical disc 101loaded in the optical disc drive by sector unit, the optical disc drivereads the ECC block containing the specified sector from the opticaldisc 101, applies error correction, replaces the data from the specifiedsector with the data to be recorded, recalculates the ECC and adds thenew ECC to the data to be recorded, and then records the ECC blockcontaining the specified sector to the optical disc 101.

A “cluster” as used below means an ECC block as described above.

FIG. 4 shows the structure of the drive information zone 214 shown inFIG. 2.

The drive information zone 214 contains a plurality of clusters 401 a,such as 2048 clusters 401 a. These clusters 401 a are numberedsequentially from cluster #1 at the inside circumference side to cluster#2, . . . cluster #2048 at the outside circumference side of the driveinformation zone 214.

Each cluster includes a plurality of sectors 401 b, such as 32 sectors401 b. These sectors 401 b are also arranged sequentially from sectors#1 at the inside circumference side to sectors #2, . . . sectors #32 atthe outside circumference side. The capacity of each sector issufficient to record one drive-specific information record.

The drive-specific information recorded to each of these sectors definesthe operating conditions of the optical disc drive required to record orplay data on a loaded optical disc 101. The drive-specific informationincludes a manufacturer identifier 402, auxiliary information 403, adrive identifier 404, and a data storage area 405. The manufactureridentifier 402 identifies the manufacturer of the optical disc drive.The drive identifier 404 is a serial number, for example, used by themanufacturer to identify that optical disc drive. The data storage area405 records information such as the recording/playback conditions, suchas the required laser power level. Because the recording/playbackconditions are stored to the data storage area 405, the drive-specificinformation is also referred to herein as the recording/playbackconditions. It will be obvious that the information stored to the datastorage area 405 could be information other than the recording/playbackconditions.

Each time a disc is loaded to a different optical disc drive,drive-specific information is generated and recorded to the disc. When adisc is reloaded in an optical disc drive to which it was previouslyloaded, the drive-specific information for that optical disc drive isread and used as the drive information for using the disc.

Whether a disc was previously loaded in a particular optical disc driveis determined by reading the drive identifier 404. Furthermore, even ifthe optical disc drive determines that the disc was previously used inthat drive, if the recording/playback conditions stored on the discdiffer from the current conditions, the drive-specific information canbe generated again. As a result, drive-specific information for the sameoptical disc drive could be recorded more than once to the same opticaldisc.

The first drive-specific information generated for a particular disc isdenoted D(1), the second record of drive-specific information is denotedD(2), and the n-th drive-specific information record is denoted D(n).

The steps for recording a new drive-specific information record to discare described next below with reference to FIG. 5, FIG. 6, FIG. 7, andFIG. 8.

As shown in FIG. 5, when a new disc is loaded to optical disc drive A,drive-specific information is generated for the first time, anddrive-specific information D(1) is written to sector #1 of cluster #1.

When the same disc is then loaded in a second optical disc drive B, asecond drive-specific information entry D(2) is generated and written tosector #1 of cluster #2 as shown in FIG. 6. The first drive-specificinformation D(1) recorded in cluster #1 is also copied to sector #2 ofcluster #2. The previously used cluster #1 is left unused.

When the same disc is then loaded in a third optical disc drive C,drive-specific information D(3) for the third drive is generated, andrecord D(3) is recorded to sector #1, cluster #3. The previous entriesD(2) and D(1) previously recorded to cluster #2 are also copied in thesame sequence to sector #2 and sector #3 of cluster #3. The previouslyused clusters #1 and #2 are abandoned.

When the same disc is then loaded in a fourth optical disc drive D,drive-specific information D(4) for the fourth drive is generated, andentry D(4) is recorded to sector #1, cluster #4. The previous entriesD(3), D(2) and D(1) previously recorded to cluster #3 are also copied inthe same sequence to sectors #2, #3, and #4 of cluster #4. Thepreviously used clusters #1, #2, and #3 are abandoned.

As shown in FIG. 9, when the same disc is loaded in a k-th (where k is apositive integer) optical disc drive K, the k-th drive-specificinformation D(k) is generated and written to sector #1 of the k-thcluster #k. If k≦32, all previous entries D(k−1) . . . D(2), D(1)written to the last-recorded cluster #(k−1) are also copied in the samesequence to sectors #2, #3, . . . #k of k-th cluster #k. If k>32 (thesituation shown in FIG. 9), the drive-specific information entries tothe last-recorded entry, that is, D(n+30), D(n+29), . . . D(n+1), D(n)(where n=k−31) recorded to the last-recorded cluster #(k−1) are copiedin the same sequence to the remaining sectors #2, #3, . . . #k ofcluster #k. Entry D(n−1) is not recorded because the sectors are filledwhen entry D(n) is recorded. The previously used clusters #1, #2, . . .#(k−1) are abandoned.

Note that the k-th drive is not necessary the k-th different drive, andcould be a drive to which the disc was previously loaded, such asoptical disc drive A when optical disc drive A was not used for aspecified period of time (such as six months), or the optical disc driveA settings were changed, or an environmental temperature sensor disposedin the optical disc drive A senses a temperature different from thetemperature the last time the disc was loaded, for example.

As shown in FIG. 10, when the same disc is loaded in a (k+1)-th opticaldisc drive K+1, the (k+1)-th drive-specific information D(k+1) isgenerated and written to sector #1 of the (k+1)-th cluster #(k+1). Thedrive-specific information entries to the last-recorded entry, that is,D(n+31), D(n+30), D(n+29), . . . D(n+1) recorded to the last-recordedk-th cluster #(k) are copied in the same sequence to the remainingsectors #2, #3, . . . #k of cluster #(k+1). Entry D(n) is not recordedbecause the sectors are filled. The previously used clusters #1, #2, . .. #(k) are abandoned.

Up to 32 records of drive-specific information, that is,recording/playback conditions, can thus be recorded in one cluster. Thedrive-specific information is recorded chronologically from the newestto oldest based on when the entry was written to the optical disc 101.The 32 drive-specific information entries are thus recorded with theentry most recently recorded to the optical disc 101 in the first sectorof the cluster and the oldest of the 32 entries recorded in the lastsector of cluster #k.

In addition, drive-specific information, that is, recording/playbackconditions determined by a new learning process are recorded to thebeginning of cluster #k. As a result, drive information area 502 isalways assured of containing up to 32 recording/playback conditionsentries including the results of the most recent learning process.

The drive information zone 214 contains N ECC blocks (clusters). Each ofthe N ECC blocks (clusters) contains a plurality of sectors. Each of theplural drive-specific information entries contained in each cluster 401a is recorded to a single corresponding sector. N is any positiveinteger value or 1 or more, and in this example is 2048.

FIG. 11 is a block diagram of an optical disc drive. Shown in FIG. 11are an optical disc 101, a disc detection device 4 for detecting if adisc has been loaded, a controller 6, memory 8; and a disc drive 10 forreading and writing the 101. The memory 8 stores information specific tothe optical disc drive, including the manufacturer identifier 402identifying the manufacturer of the optical disc drive, auxiliaryinformation 403, and a drive identifier 404 such as a serial number usedby the manufacturer to identify that optical disc drive.

Operation of this optical disc drive is shown in FIG. 12 and describedbelow.

The disc detection device 4 detects if an optical disc has been loaded(step S1).

The drive information area of the lead-in area on the loaded disc isthen accessed (step S2).

Starting from the first cluster, each cluster is inspected to determineif the cluster has been recorded or not in order to detect the firstunrecorded cluster (step 33).

The last-recorded cluster, which is the recorded cluster immediatelypreceding the first unrecorded cluster, is then decoded (step S4).

The sector number m is reset to 1 in order to read the sectors of thedecoded last-recorded cluster starting from the first sector (step S5).

Sector m (where m=1 at this time) is then read (step S6).

The drive identifier 404 stored in memory 8 in the optical disc drive isthen detected (the detected drive identifier is called the “detectedidentifier”), the drive identifier recorded in sector m (the “registeredidentifier”) is read, and whether the detected identifier and registeredidentifier are the same is determined. If the identifiers are the same,controls skips to step S13. If the identifiers are not the same, controlgoes to step S8.

In step S13, the drive control information recorded in the data storagearea 405 of the target sector (sector m of the last-recorded cluster ifstep S13 is entered from step S7) is read and used to configure the discdrive 10. The disc drive 10 can then proceed with reading/writing thedisc based on the read drive control information without first testwriting or test reading. As a result, the time between loading the discand starting to read or write the disc can be shortened.

In step S8, sector number m is incremented one.

Whether sector number m is greater than the maximum sector numberm_(max) is then determined (step S9). In this example, maximum sectornumber m_(max) is 32. If sector number m is less than or equal tom_(max), the procedure loops back to step S6 and steps S7 and S8 repeat.If sector number m is greater than M_(max), control goes to step S10.

In step S10, the disc drive 10 tests writing and reading the opticaldisc 101 in the test zone 212 to determine the optimum power level forthe loaded disc, and thus compiles drive-specific information for theoptical disc drive. This drive-specific information is the firstdrive-specific information acquired from that optical disc drive forthat disc, and is thus referred to herein as new drive-specificinformation.

The new drive-specific information is then written to the first sector(sector #1) of the first unrecorded cluster (step S11).

The information from all sectors other than the last sector (that is,sector #1 to sector #31) in the last-recorded cluster is then copied tothe sectors other than the first sector (that is, sector #2 to sector#32) in the first unrecorded cluster (step S12).

In step S13, the drive control information recorded in the data storagearea 405 of the target sector (the first sector of the first unrecordedcluster if step S13 is entered from step S12) is used to configure thedisc drive 10. The disc drive 10 can then proceed with reading/writingthe disc.

Note that when new drive-specific information is produced the disc drive10 could be configured based on that information before the informationis recorded to a sector as described above.

As will be known from the above, when a single disc is loaded into thesame optical disc drive, the optical disc drive accesses the driveinformation zone 214, checks the drive-specific information clusterssequentially from the first cluster to find the first unrecordedcluster, and then starts reading from the first sector in thelast-recorded cluster, that is, the cluster before the first unrecordedcluster. As a result, the drive-specific information is readsequentially from the newest to the oldest information. That is, thedrive-specific information is arranged so that the last-recordedinformation is read first.

As will also be known from the above, one cluster is used for onerecording of drive-specific information. Cluster #1 is used for thefirst recording, cluster #2 is used for the second recording, and soforth, proceeding sequentially from the inside circumference side of thedisc. Therefore, when drive-specific information has been recorded ktimes, cluster #1 to cluster #k are recorded, and the newest informationis stored in cluster #k.

Updating the drive information area 401 thus assures that the mostrecently recorded cluster #(k+1) in the drive information area 401always contains the 32 newest recording/playback conditions 401 b, andby reading this cluster first, the learning time can be shortened if therecording/playback conditions that can be used are found.

By thus structuring the drive information area 401 so that the so thatdata is updated by appending to unrecorded areas of the disc, the methodof the present invention is not limited to use with rewritable opticaldisc media, and can also be used with write-once optical disc media.

Embodiment 2

FIG. 13 shows the structure of a single-side, two-layer optical discaccording to a second embodiment of the present invention.

As shown in FIG. 13 this optical disc has a first substrate 601, firstrecording layer 602, a space layer 603 of an adhesive resin, forexample, a second recording layer 604, and a second substrate 605.

The laser beam is emitted from the second substrate 605 side of the discshown in FIG. 13 to read and write data to the first recording Layer 602and second recording layer 604.

A single or multiple spiral tracks could be formed on the firstrecording layer 602 and second recording layer 604.

FIG. 14 shows the logic structure of a two-layer optical disc accordingto this embodiment of the invention.

The prerecorded area 701 a of the first recording layer stores, forexample, identification data for the two-layer optical disc recorded ina wobble track, embossed pits, or wobbled embossed pits.

The prerecorded area 701 a includes a protected zone 703 a as a buffer,and a control data zone 704 a. The control data zone 704 a stores atleast one of the following as optical disc identification information:disc type, disc capacity, disc structure, channel bit, data zone addressinformation, data rate, maximum playback power, recording powerinformation, recording pulse position information, and disc-specificinformation.

The information recorded in the control data zone 704 a on the firstrecording layer could be information relating only to the firstrecording layer, or information relating to the first recording layerand information relating to the second recording layer.

The prerecorded area 701 b on the second recording layer is located atthe same radial position as the prerecorded area 701 a of the firstrecording layer.

This prerecorded area 701 b also includes a protected zone 703 b as abuffer, and a control data zone 704 b. The control data zone 704 bstores at least one of the following as optical disc identificationinformation: disc type, disc capacity, disc structure, channel bit, datazone address information, data rate, maximum playback power, recordingpower information, recording pulse position information, anddisc-specific information.

The information recorded in the control data zone 704 b on the secondrecording layer could be information relating only to the firstrecording layer, or information relating to the first recording layerand information relating to the second recording layer. The control datazones 704 a and 704 b could store the same information.

The data recording area 702 a on the first recording layer includes aprotected zone 705 a in which data is not recorded, a reserved zone 706a enabling future development, a test zone 707 a used for testing theoptical disc, a buffer zone 708 a, a drive information zone 709 a usedfor storing information such as optical disc characteristics, a bufferzone 710 a, a user data recording zone 711 a for recording user data, abuffer zone 712 a, a reserved zone 713 a enabling future development, abuffer zone 714 a, and a protected zone 715 a in which data is notrecorded.

If the track pitch differs in the prerecorded area 701 a and datarecording area 702 a, the protected zone 705 a can be used as a trackpitch transition area.

The data recording area 702 b on the second recording layer likewiseincludes a protected zone 705 b in which data is not recorded and whichcan be used as a track pitch transition area when the track pitchdiffers in the prerecorded area 701 b and data recording area 702 b. Theprotected zone 705 b on the second recording layer is located at thesame radial position as the protected zone 705 a on the first recordinglayer.

The data recording area 702 b on the second recording layer alsoincludes a test zone 707 b used for testing the optical disc. This testzone 707 b is located at the same radial position as, or at a radialposition on the inside circumference side of, the reserved zone 706 a onthe first recording layer.

The data recording area 702 b also includes a reserved zone 706 b forfuture developments. This reserved zone 706 b is located at the sameradial position as, or at a radial position on the inside circumferenceside of, the test zone 707 a on the first recording layer.

The data recording area 702 b on the second recording layer alsoincludes a buffer zone 708 b, which is located at the same radialposition as the buffer zone 708 a on the first recording layer.

The data recording area 702 b on the second recording layer alsoincludes a reserved zone 709 b to which data is not recorded. Thisreserved zone 709 b is located at the same radial position as the driveinformation zone 709 a of the first recording layer.

The data recording area 702 b on the second recording layer alsoincludes a buffer zone 710 b, a user data recording zone 711 b forrecording user data, another buffer zone 712 b, another reserved zone713 b enabling future developments, a buffer zone 714 b, and a protectedzone 715 b to which data is not recorded. Each of these zones is locatedat the same radial position as the corresponding buffer zone 710 a, userdata recording zone 711 a, buffer zone 712 a, reserved zone 713 aenabling future developments, buffer zone 714 a, and protected zone 715a to which data is not recorded in the first recording layer.

When the disc is spun for reading and writing along the tracks on thefirst and second recording layers, the read/write direction of thetracks on the first recording layer is from inside to outsidecircumference as indicated by arrow 716 a in FIG. 14, and the read/writedirection of the tracks on the second recording layer is from outside toinside circumference as indicated by arrow 716 b.

Because the control data zones are located at the same radial positionin the first and second recording layers with the disc arrangementaccording to this embodiment of the invention, the control data can beread from either recording layer, and the identification information canthus be acquired more quickly.

Furthermore, because a reserved zone 709 b where data is not recorded islocated on the second recording layer at the same radial position as thedrive information zone 709 a on the first recording layer, the driveinformation zone 709 a can be read or written through a second recordinglayer that is always in the same state (that is, blank in thisembodiment). As a result, the drive information can be read and writtenconsistently and stably.

Yet further, because a reserved zone where data is not recorded isdisposed at the same radial position as at least part of the test zonewith the disc format according to the present invention, disc testingcan be conducted under consistently stable conditions through anotherlayer that is always in the same state (that is, blank in thisembodiment).

It will be obvious to one with ordinary skill in the related art thatthe structure of drive information zone 709 a in this embodiment of theinvention could be structured as shown in any of FIG. 4, FIG. 16, FIG.17, and FIG. 18.

Embodiment 3

FIG. 13 shows the structure of a single-side, two-layer optical discaccording to a third embodiment of the present invention.

FIG. 15 shows the logic structure of a two-layer optical disc accordingto this embodiment of the invention.

The prerecorded area 801 a of the first recording layer stores, forexample, identification data for the two-layer optical disc recorded ina wobble track, embossed pits, or wobbled embossed pits.

The prerecorded area 801 a includes a protected zone 803 a as a buffer,and a control data zone 804 a. The control data zone 804 a stores atleast one of the following as optical disc identification information:disc type, disc capacity, disc structure, channel bit, data zone addressinformation, data rate, maximum playback power, recording powerinformation, recording pulse position information, and disc-specificinformation.

The information recorded in the control data zone 804 a on the firstrecording layer could be information relating only to the firstrecording layer, or information relating to the first recording layerand information relating to the second recording layer.

The prerecorded area 801 b on the second recording layer is located atthe same radial position as the prerecorded area 801 a of the firstrecording layer.

This prerecorded area 801 b also includes a protected zone 803 b as abuffer, and a control data zone 804 b. The control data zone 804 bstores at least one of the following as optical disc identificationinformation: disc type, disc capacity, disc structure, channel bit, datazone address information, data rate, maximum playback power, recordingpower information, recording pulse position information, anddisc-specific information.

The information recorded in the control data zone 804 b on the secondrecording layer could be information relating only to the firstrecording layer, or information relating to the first recording layerand information relating to the second recording layer. The control datazones 804 a and 804 b could store the same information.

The data recording area 802 a on the first recording layer includes aprotected zone 805 a in which data is not recorded, a buffer zone 806 a,a drive information zone 807 a used for storing information such asoptical disc characteristics, a buffer zone 808 a, a test zone 809 aused for testing the optical disc, a reserved zone 810 a for futuredevelopments, a user data recording zone 811 a for recording user data,a buffer zone 812 a, a reserved zone 813 a enabling future development,a buffer zone 814 a, and a protected zone 815 a in which data is notrecorded.

If the track pitch differs in the prerecorded area 801 a and datarecording area 802 a, the protected zone 805 a can be used as a trackpitch transition area.

The data recording area 802 b on the second recording layer likewiseincludes a protected zone 805 b in which data is not recorded and whichcan be used as a track pitch transition area when the track pitchdiffers in the prerecorded area 801 b and data recording area 802 b. Theprotected zone 805 b on the second recording layer is located at thesame radial position as the protected zone 805 a on the first recordinglayer.

The data recording area 802 b on the second recording layer likewiseincludes a reserved zone 807 b in which data is not recorded. Thisreserved zone 807 b is located at the same radial position as the driveinformation zone 807 a on the first recording layer.

The data recording area 802 b of the second recording layer alsoincludes a reserved zone 810 b allowing for future developments. Thisreserved zone 810 b is located at the same radial position as, or at aradial position on the inside circumference side of, the test zone 809 aon the first recording layer.

The data recording area 802 b on the second recording layer alsoincludes a user data recording zone 811 b for recording user data,another buffer zone 812 b, another reserved zone 813 b enabling futuredevelopments, a buffer zone 814 b, and a protected zone 815 b to whichdata is not recorded. Each of these zones is located at the same radialposition as the corresponding user data recording zone 811 a, bufferzone 812 a, reserved zone 813 a enabling future developments, bufferzone 814 a, and protected zone 815 a to which data is not recorded inthe first recording layer.

When the disc is spun for reading and writing along the tracks on thefirst and second recording layers, the read/write direction of thetracks on the first recording layer is from inside to outsidecircumference as indicated by arrow 816 a in FIG. 15, and the read/writedirection of the tracks on the second recording layer is from outside toinside circumference as indicated by arrow 816 b.

Because the control data zones are located at the same radial positionin the first and second recording layers with the disc arrangementaccording to this embodiment of the invention, the control data can beread from either recording layer, and the identification information canthus be acquired more quickly.

Furthermore, because a reserved zone 807 b where data is not recorded islocated on the second recording layer at the same radial position as thedrive information zone 807 a on the first recording layer, the driveinformation zone 807 a can be read or written through a second recordinglayer that is always in the same state (that is, blank in thisembodiment). As a result, the drive information can be read and writtenconsistently and stably.

Yet further, because a reserved zone where data is not recorded isdisposed at the same radial position as at least part of the test zonewith the disc format according to the present invention, disc testingcan be conducted under consistently stable conditions through anotherlayer that is always in the same state (that is, blank in thisembodiment).

It will be obvious to one with ordinary skill in the related art thatthe structure of drive information zone 807 a in this embodiment of theinvention could be structured as shown in any of FIG. 4, FIG. 16, FIG.17, and FIG. 18.

Embodiment 4

FIG. 16 shows the structure of the drive information zone 214 shown inFIG. 2 according to a fourth embodiment of the present invention. FIG.17 and FIG. 18 show variations of the same.

As shown in FIG. 16, each cluster is segmented into a plurality ofsectors (32 sectors in this example) as described in the firstembodiment. This fourth embodiment differs from the first embodiment inthat in addition to the drive-specific information, disc-specificinformation S(i) is recorded to one sector.

This disc-specific information S(i) includes, for example, the lastaddress at which user data is recorded, and the last address that wasused in the test zone. Drive-specific information D(1) is recorded tosector #1 in cluster #1, and disc-specific information S(1) is recordedto sector #2 in cluster #1. This disc-specific information S(1) containsthe last address information following the end of the recorded userdata, and the last address information identifying the last address usedin the test zone.

When the same disc is loaded in a second optical disc drive, thedrive-specific information D(2), D(1) is recorded to sector #1 andsector #2, respectively, in cluster #2, and disc-specific informationS(2) is recorded to sector #3, cluster #2. This disc-specificinformation S(2) records the updated last address information followingthe address to which the user data was appended, and the updated lastaddress information identifying the last address used in the test zone.

One sector in each cluster is thus used to record disc-specificinformation. The sector to which the disc-specific information isrecorded could be the last used sector in each cluster (as shown in FIG.16), the first sector in each cluster (as shown in FIG. 17), or someother desirable sector.

The disc-specific information could be updated each time newdrive-specific information is added, or each time a specific amount ofdata is written to the user data recording area. FIG. 18 shows a case inwhich the disc-specific information is updated each time a specificamount of data is written to the user data recording area.

Referring to FIG. 18, when the disc is loaded in a second optical discdrive, drive-specific information D(2) and D(1) is recorded to sector #2and sector #3 of cluster #2, and the disc-specific information S(2) iswritten to sector #1 of cluster #2. This disc-specific information S(2)records the updated last address information following the address towhich the user data was appended, and the updated last addressinformation identifying the last address used in the test zone.

If a specified volume F of user data is then recorded to the disc usingthe same optical disc drive, the same drive-specific information D(2),D(1) is copied from cluster #2 to sector #2 and sector #3 of cluster #3,and the updated disc-specific information S(3) is recorded to sector #1of cluster #3.

This specified volume F isF=2S/Gwhere G is the number of clusters (G=2048, for example), and S is thecapacity of the user data recording area. In this case, thedisc-specific information S(i) will be updated G/2 times even if theentire user data recording area is written by the same optical discdrive. Half of the total number of clusters will be left unused in thedrive information area, and can be used to record additional accessinformation.

The specified volume F could, of course, be otherwise defined,including:F=S/G,F=3S/G,F=4S/G, orF=5S/G.

Referring to FIG. 17, when the number of drive-specific informationrecords D(n) increases to 31, D(1) to D(31) are written from sector #32to sector #2 in the chronological order in which the data was generated,and the most recent data D(31) is written to sector #2. Thedisc-specific information S(i) is recorded in sector #1.

By thus structuring the drive information area 901 so that the so thatdata is updated by appending to unrecorded areas of the disc, the methodof the present invention is not limited to use with rewritable opticaldisc media, and can also be used with write-once optical disc media.

Furthermore, because both drive-specific information and disc-specificinformation are recorded in one cluster (ECC block), both thedrive-specific information and disc-specific information can be updatedby updating only one cluster. The drive-specific information cantherefore be used efficiently with particularly noticeable benefit inwrite-once optical discs that can only be recorded once.

A plurality of recording/playback condition records are recorded to anoptical disc according to the present invention chronologically in theorder in which the entries are recorded to the disc. As a result, themost recently acquired recording/playback conditions are alwayscontained in the drive information.

Furthermore, in a multilayer disc according to the present invention thearea of one layer overlapping the drive information area in anotherlayer is left unrecorded, thereby assuring that the drive informationcan always be read under stable conditions.

The present invention is based on the previously filed Japanese PatentApplications 2002-192192 and 2002-310094, the content of which is herebyincorporated by reference.

Although the present invention has been described in connection with thepreferred embodiments thereof with reference to the accompanyingdrawings, it is to be noted that various changes and modifications willbe apparent to those skilled in the art. Such changes and modificationsare to be understood as included within the scope of the presentinvention as defined by the appended claims, unless they departtherefrom.

1. An optical disc drive for recording on and reading from an opticaldisc having a data recording area for recording data, and a driveinformation area for recording drive-specific information, wherein thedrive information area comprises a plurality of clusters, each clustercomprises a plurality of sectors, each sector has capacity for storingone record of drive-specific information, and the plural records ofdrive-specific information are arranged in an order in which the pluralrecords were recorded with a last-recorded record of the plural recordsof drive-specific information located in a first sector of a currentcluster following a last sector of a previous cluster, the optical discdrive comprising: a detection device operable to detect if the opticaldisc was loaded; a drive device operable to read from and write to theoptical disc; a memory operable to store at least a manufactureridentifier for identifying the manufacturer of the optical disc drive, adrive identifier containing at least a serial number of the optical discdrive, and recording/playback conditions including a required laserpower level; and a controller operable to control the drive device,wherein the drive device is controlled by the controller, and when theoptical disc is loaded accesses the drive-specific information, detectsa first unrecorded cluster, reads a last-recorded cluster immediatelypreceding the first unrecorded cluster, and sets a write power levelbased on the drive-specific information in the last-recorded cluster;and a writing unit operable to write, at a time of recording newdrive-specific information, the new drive-specific information to afirst sector in a new cluster, and to write information from all sectorsexcept a last sector in an immediately preceding cluster to remainingsectors following the first sector in the new cluster which includes thenew drive-specific information, the immediately preceding cluster beingrecorded with all previous records of drive-specific information,wherein the new cluster is immediately next to the preceding cluster inthe same drive information area in the optical disc.
 2. An optical discdrive as described in claim 1, wherein setting the write power levelbased on the drive-specific information in the last-recorded clusterdetermines whether drive-specific information storing the same driveidentifier as the drive identifier of the optical disc drive iscontained in the last-recorded cluster, if the drive-specificinformation storing the same drive identifier is detected, sets thewrite power level based on that drive-specific information, and if thedrive-specific information storing the same drive identifier is notdetected, sets a new write power level by a new learning process andgenerates the new drive-specific information, and stores the newdrive-specific information to the first sector in the new cluster, andstores information from all sectors except the last sector in theimmediately preceding cluster to the remaining sectors following thefirst sector in the new cluster.
 3. An optical disc driving method forrecording on and reading from an optical disc having a data recordingarea for recording data, and a drive information area for recordingdrive-specific information, wherein the drive information area comprisesa plurality of clusters, each cluster comprises a plurality of sectors,each sector has capacity for storing one record of drive-specificinformation, and the plural records of drive-specific information arearranged in an order in which the plural records were recorded with alast-recorded record of the plural records of drive-specific informationlocated in a first sector of a current cluster following a last sectorof a previous cluster, the optical disc driving method comprising:detecting if the optical disc was loaded; accessing the driveinformation area when the optical disc is loaded; detecting a firstunrecorded cluster; reading a last-recorded cluster immediatelypreceding the first unrecorded cluster; setting a write power levelbased on the drive-specific information in the last-recorded cluster;and writing, at a time of recording new drive-specific information, thenew drive-specific information to a first sector in a new cluster, andwriting information from all sectors except a last sector in animmediately preceding cluster to remaining sectors following the firstsector in the new cluster which includes the new drive-specificinformation, the immediately preceding cluster being recorded with allprevious records of drive-specific information, wherein the new clusteris immediately next to the preceding cluster in the same driveinformation area in the optical disc.
 4. An optical disc driving methodas described in claim 3, wherein setting the write power level based onthe drive-specific information in the last-recorded cluster determineswhether drive-specific information storing the same drive identifier asthe drive identifier of the optical disc drive is contained in thelast-recorded cluster, if the drive-specific information storing thesame drive identifier is detected, sets the write power level based onthat drive-specific information, and if the drive-specific informationstoring the same drive identifier is not detected, sets a new writepower level by a new learning process and generates the newdrive-specific information, and stores the new drive-specificinformation to the first sector in the new cluster, and storesinformation from all sectors except the last sector in the immediatelypreceding cluster to the remaining sectors following the first sector inthe new cluster.